Hey everyone. Yesterday I noticed my engine is starting to make a whining noise almost like a supercharger, but I don't have one... The noise increases with RPM, and seems most noticeable around 1500-2000 rpms. After that it gets kinda drowned out with the regular engine noise.
At first I thought it was the power steering so I siphoned some of it out a few times and cleaned the filter in the process. I got a little dirt off of it, but it wasn't bad and the noise is still there.
The noise isn't in the drivetrain as it still makes the noise while sitting in park.
I think it may be the alternator because after running it for just a few minutes from a dead cold start the silver case on the alternator was too hot to touch. Everything else was still cool enough to touch, the scangauge said the coolant temp when I shut it off was 114*F.
I let it warm all the way up and all the pulleys are still cool to the touch, including the alternator pulley, but the alternator case itself was very hot at this point. I think the two things it could be are the alternator or the lower tensioner pulley, but that pulley was cool to the touch so I wouldn't think it would be that. It also kinda sounds like it is coming from the alternator area, but it is hard to tell.
The truck is just a few miles shy of 170k right now and the alternator appears to be the original. I'm leaning towards it being that.
Here's a video showing the noise.
Any suggestions or help is greatly appreciated. I'd like to get my truck back to full strength as quick as possible.